package com.ly.thread;
import java.util.concurrent.ExecutionException;
import	java.util.concurrent.ForkJoinTask;

import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.RecursiveTask;

class MyTask extends RecursiveTask<Integer> {

    private static final Integer ADJUST_VALUE = 10;

    private int begin;

    private int end;

    private int result;

    public MyTask(int begin,int end) {
        this.begin = begin;
        this.end = end;
    }

    @Override
    protected Integer compute() {
        if((end - begin) <= ADJUST_VALUE) {
            for(int i=begin;i<=end;i++) {
                result += i;
            }
        }else {
            int middle = ( end + begin )/2;
            MyTask task1 = new MyTask(begin,middle);
            MyTask task2 = new MyTask(middle+1,end);
            task1.fork();
            task2.fork();
            result = task1.join()+task2.join();
        }
        return result;
    }
}


public class ForkJoinDemo {

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        MyTask task = new MyTask(0,100);
        ForkJoinPool forkJoinPool = new ForkJoinPool();
        ForkJoinTask<Integer> forkJoinTask = forkJoinPool.submit(task);
        System.out.println(forkJoinTask.get());
        forkJoinPool.shutdown();
    }
}
